1. Field of the Invention
The present invention relates to a head-protecting airbag apparatus including an airbag capable of protecting the head of an occupant. An airbag of a head-protecting airbag apparatus is deployed and inflated downward by allowing inflation gas to flow thereinto from an upper edge of a window (side window) of a vehicle.
2. Background Art
In the related art, as head-protecting airbag apparatuses, there is one shown in JP-A-2007-69721. In this airbag apparatus, an airbag is smoothly deployed and inflated toward the interior of a vehicle from the vicinity of an upper end of a pillar garnish of a rear pillar, with a simple configuration without using a member to be mounted to the body side, such as a jump platform. In addition, the pillar garnish covers the interior of the rear pillar.
The airbag of this head-protecting airbag apparatus includes a rear inflatable portion and a gas supply passage. The rear inflatable portion is arranged at a rear portion of the airbag to cover the vehicle interior of a rear window (rear side window) at a side of a backseat of a vehicle and the rear pillar. A gas supply passage is a portion that allows inflation gas to flow into the rear inflatable portion. The rear inflatable portion includes an inflatable main body portion, an upper edge inflatable portion, and a branch inflatable portion. The upper edge inflatable portion is arranged above the inflatable main body portion to communicate with a rear portion of the gas supply passage. The branch inflatable portion is arranged at the front of the inflatable main body portion to communicate with a rear end of the gas supply passage, and allow inflation gas to flow into the inflatable main body portion. Moreover, in this airbag, the folded upper edge inflatable portion and gas supply passage are housed at a position of the vehicle exterior of the folded inflatable main body portion and branch inflatable portion so that, upon deployment and inflation, the inflatable main body portion can be pushed out toward the interior while riding over an upper end of the pillar garnish.
In this head-protecting airbag apparatus, the airbag is folded and housed at an upper edge of the window. Then, if inflation gas flows into the airbag, the gas supply passage arranged along a longitudinal direction and the upper edge inflatable portion inflate rapidly from the front side to the rear side in the rear inflatable portion. In that case, the gas supply passage and the upper edge inflatable portion push out the inflatable main body portion and the branch inflatable portion, which are arranged therebelow upon the completion of inflation, toward the interior. Therefore, the inflatable main body portion has been smoothly deployed so as to cover the interior of the rear pillar and the rear window along with the branch inflatable portion while riding over the upper end of the pillar garnish.
Additionally, in this head-protecting airbag apparatus, a region at least at a front end at a lower edge of the upper edge inflatable portion is arranged below an interior parting line of an upper end of the pillar garnish and a lower edge of an airbag cover in a state before the opening of the airbag cover upon the completion of inflation of the airbag. Therefore, at least a region at the front end of the upper edge inflatable portion is formed as a wedging inflatable portion. That is, this wedging inflatable portion is located at the interior of the upper end of the pillar garnish, and is inflated so as to be like a wedge between the interior of the upper end of the pillar garnish and the exterior of the lower edge of the airbag cover located above the rear pillar. The wedging inflatable portion greatly opens the airbag cover toward the interior, to maintain the open state. Therefore, the inflatable main body portion is able to complete its inflation by increasing the thickness thereof without protruding greatly toward the interior below the airbag cover that is greatly opened by the upper edge inflatable portion at the upper side of the rear pillar after being deployed so as to cover the interior of the rear pillar and the rear window. That is, the inflatable main body portion is able to complete its inflation by increasing the thickness thereof from a front portion toward a rear portion at a lower edge and from a lower edge toward an upper edge at the rear portion so as to extend along the interior of the rear window without protruding greatly toward the interior after being deployed.
However, in the related-art airbag, the whole region of the inflatable main body portion and the upper edge inflatable portion is vertically separated by a partitioning portion (closing portion). This partitioning portion has a rear end coupled to a gas non-inflow portion of the rear edge of the airbag, and is disposed so as to extend forward from the coupled portion. That is, this partitioning portion divides the inflatable main body portion and the upper edge inflatable portion in the whole region between the inflatable main body portion and the upper edge inflatable portion so as to obstruct the rear end of the upper edge inflatable portion.
Therefore, in this airbag apparatus, in a case where the head of an occupant is received and stopped by the branch inflatable portion during the deployment and inflation of the airbag, there is a concern that the flow of inflation gas to the inflatable main body portion may be suppressed, and the inflation gas may flow only into the upper edge inflatable portion. If the inflation gas flows only into the upper edge inflatable portion, the vicinity of the rear lower portion of the inflatable main body portion cannot be thickly swelled. Moreover, at this time, if the upper edge inflatable portion leaks inflation gas from the peripheral edge thereof due to a rise in internal pressure, the vicinity of the rear lower portion of the inflatable main body portion cannot further be thickly swelled.